Principles of Liberalism
The liberal core
Liberalism begins with the individual: each person has worth and is entitled to rights that government should not casually override. From that starting point follow the principles you must be able to name.
Concepts to know
Individual rights and freedoms - conscience, religion, expression, assembly, association, and security of the person. Rule of law - everyone, including rulers, is subject to known, equally applied law. Limited government and constitutionalism - power is divided, written down, and can be challenged. Consent of the governed - authority rests on the will of the people, expressed through representative democracy and elections. Economic freedom - private property, competition, self-interest, and the profit motive. Equality - before the law, and of opportunity; equality of outcome is a different, contested idea. Pluralism and tolerance - a free society contains competing beliefs and must protect even unpopular ones.
Traps
Distinguish negative liberty ('freedom from' interference) from positive liberty ('freedom to' act or flourish). Rule of law is not the same as majority rule - a majority may not simply vote away a minority's rights. Equality of opportunity does not promise equal results. No liberal right is absolute; each is balanced against others and the common good.
Rule of thumb
For any scenario, ask: whose freedom is being limited, by whom, and which principle justifies it? Then test whether the limit is proportionate and consistent with the other principles. A government that limits expression to protect reputation is doing something different from one that limits it to protect itself.